A Single-center, randomized, prospective, experimental, double-blind comparison study for effects of preoperative scopolamine patch application on the postoperative nausea and vomiting in microvascular decompression surgery

1. Study design and plan

   1-1) Sixty envelopes will be prepared: Thirty envelopes of scopolamine patch for experimental group and 30 of placebo patch for control group. Each envelope will be tagged for QR code, randomly mixed and numbered from 1 to 60. QR code will be identified after discontinuation of study, so both researchers and subjects would not know in which group the envelope is belonged to.

   1-2) Patch will be applied under the ear of the opposite side of operation, at 9 p.m. of the day before the operation day.

   1-3) Nausea will be assessed by Visual Analogue Scale (VAS) immediate after arrival at a recovery room and the ward. After that, nausea will be continuously assessed every 4 hour (4hr, 8hr, 12hr, 16hr, 20hr, and 24hr after surgery) and a number of vomiting will also be counted. Basic clinical characteristics and the number of antiemetic administration will be identified through medical records.

2. Efficacy assessment

   2-1) Degree of nausea: Visual Analogue Scale (VAS) Subjects will describe their subject degree of nausea by VAS score, just immediate after arrival at a recovery room or the ward and 4hr, 8hr, 12hr, 16hr, 20hr, and 24hr after surgery. Respondents specify their degree of nausea by indicating a point along a continuous 10cm line between two end-points; left one is for "No nausea" and the right one for "Very severe nausea". Scoring is based on the length from left point and higher score means more severe degree of nausea.

   2-2) Number of vomiting Number of vomiting is counted from immediate after arrival at recovery room or the ward, 4hr, 8hr, 12hr, 16hr, 20hr, and 24hr after operation and will be recorded. If there is no vomiting, it will be recorded as "0".

   2-3) Number of antiemetic administration It will be recorded from immediate after arrival at recovery room or the ward, 4hr, 8hr, 12hr, 16hr, 20hr, and 24hr after operation. The kind of antiemetic used and the dosage or number of administration can be identified through medical records.

   2-4) Type of antiemetic and time of administration 2-4-1) PRN) Meckool 10mg/2ml 1amp IVs When VAS is more than 5 or when subjects want at minimum interval of 6hour and maximum of three times. If there is no improvement, it will be noticed.

   2-4-2) PRC) Nasea 0.3mg 1amp IVs

3. Statistical plans

   3-1) General characteristics and clinical characteristics will be analyzed by frequency, percentage, mean value and standard deviation.

   3-2) Homogeneity of variances between experimental group and control group will be analyzed by Chi-square test, t-test and Fisher's exact test 3-3) Degree of nausea between experimental group and control group at recovery room or the ward, 4hr, 8hr, 12hr, 16hr, 20hr, and 24hr after operation will be analyzed by Student's t-test.

   3-4) Number of vomiting and antiemetic administration between experimental group and control group will be analyzed by Fisher's exact test.

   3-5) Hospitalization period between experimental group and control group will be analyzed by Student's t-test.

4. Experimental group of scopolamine patch application will be expected to have less severity of nausea and fewer numbers of vomiting or antiemetic usages. Ultimately, this may relate to hospitalization period and it will be decreased.

Inclusion Criteria:

1. Those of either hemi-facial spasm or trigeminal neuralgia, who undergo microvascular decompression (MVD), understand study objectives and voluntarily consent with participation.
2. Adequate communication ability enough to understand and answer the questionnaire.
3. Age ≥ 18 years, and ≤ 65 years.
4. ASA Physical Status Classification from 1 to 2. Class 1: A normal healthy patient Class 2: A patient with mild systemic disease
5. Those who is discharged to general ward, not intensive care unit (ICU) after operation
6. Normal liver or kidney function

Exclusion Criteria:

1. More than one craniotomy in the same period of admission
2. Pregnant or lactating women
3. Narrow-angle glaucoma
4. Pyloric stenosis, intestinal obstruction, bladder obstruction
5. Bradycardia
6. Voiding difficulty such as benign prostate hypertrophy (BPH)
7. Any history of hypersensitivity to ointment base or scopolamine patch